The Senate passed the bill 64-35, sending it to the president's desk for signature.

But Baldwin -- one of just six Dems to vote against the bill -- called the measure "missed opportunity" to reduce costs and overhaul the "flawed Medicare payment formula."

"Congress has made great bipartisan, bicameral progress to enact real and lasting reforms that could reduce Medicare costs and improve the quality of care for today’s seniors," Baldwin said. "But this deal is another band-aid that kicks the can down the road with a 17th patch, which guarantees that we’ll be back in the same place in one year."